The net force must be zero
This is in accordance to Newton's first law, which states that any object in motion will remain in motion and any object at rest will remain at rest unless acted upon by an unbalanced force. An unbalanced force is one where the net force is not zero. If no unbalanced force is applied to a moving object, it will keep moving forever. The reason that we do not observe this in our daily lives is due to friction acting as the unbalanced force.
Answer:
part (a) v = 1.7 m/s towards right direction
part (b) Not an elastic collision
part (c) F = -228.6 N towards left.
Explanation:
Given,
- Mass of the first puck =
- Mass of the second puck =
- initial velocity of the first puck =
- Initial velocity of the second puck =
Part (a)
Pucks are stick together after the collision, therefore the final velocities of the pucks are same as v.
From the conservation of linear momentum,
Direction of the velocity is towards right due to positive velocity.
part (b)
Given,
Final velocity of the second puck = 
Let 
be the final velocity of first puck after the collision.
From the conservation of linear momentum,
For elastic collision, the coefficient of restitution should be 1.
From the equation of the restitution,
Therefore the collision is not elastic collision.
part (c)
Given,
Time of impact = t = 
we know that the impulse on an object due to a force is equal to the change in momentum of the object due to the collision,
Negative sign indicates that the force is towards in the left side of the movement of the first puck.
<span>In the question,' when you are sitting a few feet from the fire, your skin feels warmed. What form of heat transfer are acting to transfer heat from the fire to your skin, the correct option is A, that is, convection and radiation. Heat transfer is defined as the exchange of thermal energy between physical systems. The rate at which the heat is transfer depends on the temprature of the system and the properties of the intervening medium through which the heat is been transfered. There are three basic modes of heat transfer, these are: conduction, convection and radiation. Conduction is defined as the transfer of heat between two bodies through physical contact. When two bodies which have different temprature come in contact, there will be a transfer of heat energy between them until the two of them have the same temprature. Conduction usually occurs in solids and liquids; it occurs in gases also but it is extremely slow. Convection is the process by which heat is transfer in fluids, that is, liquids and gases. This is how convection operates: when a fluid is heated, it expands and it becomes lighter, this makes it to rise upward and move to the cooler part of the container, as it rises, it will be replaced by the unheated surrounding particles. This cycle continues until heat is evenly distributed all through the fluid. There are two types of convection: natural and forced convection. The heating of the earth surface by the sun ray is an example of natural convection while the air conditioner we use at home operates by mean of forced convection. Both conduction and convection require matter for heat transfer. Radiation is the transfer of heat from one place to another through electromagnetic waves. The hot body transfer heat by emitting electromagnetic waves. The properties of the electromagnetic waves depend on the temperature of the body. The higher the temperature the more intense the rate of emission of radiation. Radiation can occur in all objects and does not require matter for heat transfer. The heat of the sun reaches the earth surface by means of radiation. In the question given, as the air surrounding the fire were heated they rise and were replaced by the unheated air particles. The continuation of this cycle makes the heat energy to be transferred to the objects around. Thus, the heat from the fire was transferred via convection and radiation. </span>
